Method and system for implementing h-arq-assisted arq operation

ABSTRACT

A method and system for implementing hybrid automatic repeat request (H-ARQ)-assisted automatic repeat request (ARQ) in a wireless communication system are disclosed. When an H-ARQ negative acknowledgement (NACK)-to-positive acknowledgement (ACK) error occurs, the H-ARQ receiver sends an H-ARQ NACK-to-ACK error indicator to the H-ARQ transmitter unless a maximum retransmission limit has reached, a maximum time for delivery has expired or a lifespan of the failed packet has expired. The H-ARQ transmitter sends a local NACK to the ARQ transmitter so that the failed packet is recovered at an ARQ level. The H-ARQ receiver sends a local NACK to the ARQ receiver if the H-ARQ receiver does not receive the failed packet before certain conditions occur. The ARQ receiver may send a status report to the ARQ transmitter for recovery of the failed packet.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.60/754,713 filed Dec. 29, 2005, which is incorporated by reference as iffully set forth.

FIELD OF INVENTION

The present invention is related to wireless communication systems. Moreparticularly, the present invention is related to a method and systemfor implementing hybrid automatic repeat request (H-ARQ)-assistedautomatic repeat request (ARQ) in a wireless communication system.

BACKGROUND

In conventional wireless communication systems, such as wideband codedivision multiple access (WCDMA) Release 5/6, high speed datatransmission is achieved by high speed downlink packet access (HSDPA)and high speed uplink packet access (HSUPA) technologies. To improvereliability of data transmission, H-ARQ and ARQ are implemented.

FIG. 1 shows a conventional wireless communication system 100. Thesystem 100 includes a user equipment (UE) 110, a Node-B 120 and a radionetwork controller (RNC) 130. H-ARQ entities are located in a mediumaccess control (MAC) layer 112 of the UE 110 and a MAC layer 122 of theNode-B 120. Packets are assigned transmission sequence numbers (TSNs) inan H-ARQ transmitter. An H-ARQ receiver receives the packets andattempts to decode the transmitted packets. If a packet is notdecodable, the H-ARQ receiver sends a negative acknowledgment (NACK)back to the H-ARQ transmitter for retransmission of the failed packet.If a packet is correctly decoded, the H-ARQ receiver sends a positiveacknowledgment (ACK) for the packet to the H-ARQ transmitter. Uponreceiving a NACK, the H-ARQ transmitter retransmits the packet if thenumber of retransmissions of the failed packet is less than apredetermined maximum limit, and the allowed transmission time for thefailed packet has not expired. Otherwise, the failed packet is discardedand recovered at an ARQ level.

ARQ entities are located in a radio link control (RLC) layer 114 of theUE 110 and an RLC layer 132 of the RNC 130. The ARQ entities handle theretransmission of the failed packet. The ARQ entities recover packetsthat are lost due to an NACK-to-ACK misinterpretation error at the H-ARQlevel. The ARQ process in an RLC layer is quite complex with manyoptions to perform status reporting.

An H-ARQ assisted ARQ operation may be considered when both the H-ARQand ARQ functions are co-located, such as in a universal mobiletelecommunication systems (UMTS) Node-B or a long term evolution (LTE)evolved Node-B (eNode-B).

FIG. 2 shows an example of an H-ARQ-assisted ARQ operation proposed forthird generation partnership project (3GPP) standards. A transmitter 250includes an ARQ transmitter 252 and an H-ARQ transmitter 254. A receiver260 includes an ARQ receiver 262 and an H-ARQ receiver 264. The H-ARQtransmitter 254 provides a local ACK or a local NACK to the ARQtransmitter 252.

As shown in FIG. 2, a local NACK is generated when the H-ARQ transmitter254 fails the H-ARQ transmission, (e.g., due to maximum retransmissionlimit). The ARQ transmitter 252 sends an ARQ protocol data unit (PDU) xto the H-ARQ transmitter 254 (step 202). The H-ARQ transmitter 254 sendsthe ARQ PDU x to the H-ARQ receiver 264 (step 204). The ARQ PDU x is notdecodable and the H-ARQ receiver 264 sends a NACK to the H-ARQtransmitter 254 (step 206). The H-ARQ transmitter 254 retransmits theARQ PDU x to the H-ARQ receiver 264 (step 208). The ARQ PDU x is stillnot decodable and the H-ARQ receiver 264 sends another NACK to the H-ARQtransmitter 254 (step 210). At such a point, it is determined that thenumber of retransmissions for the ARQ PDU x reaches a maximumretransmission limit (step 212). The H-ARQ transmitter 254 then sends alocal NACK for the ARQ PDU x to the ARQ transmitter 252 (step 214).

A local NACK may also be generated when an NACK-to-ACK error is reportedfrom the H-ARQ receiver 264 to the H-ARQ transmitter 254. Stillreferring to FIG. 2, the ARQ transmitter 252 sends an ARQ PDU y to theH-ARQ transmitter 254 (step 216). The H-ARQ transmitter 254 transmitsthe ARQ PDU y to the H-ARQ receiver 264 (step 218). The ARQ PDU y is notdecodable and the H-ARQ receiver 264 sends a NACK to the H-ARQtransmitter 254 (step 220). However, the NACK is misinterpreted as anACK by the H-ARQ transmitter 254 and the H-ARQ transmitter 254 treatsthe ARQ PCU y as successfully transmitted. The H-ARQ receiver 264detects an NACK-to-ACK error, (e.g., when the H-ARQ receiver 264receives a new PDU via the same H-ARQ process while waiting forretransmission of the ARQ PDU y), (step 222). The H-ARQ receiver 264sends a NACK-to-ACK error indicator to the H-ARQ transmitter 254 (step224). Upon receipt of the NACK-to-ACK error indicator, the H-ARQtransmitter 254 sends a local NACK to the ARQ transmitter 252 and theARQ PDU y is recovered at an ARQ level (step 226).

As shown in FIG. 2, a local ACK is generated when none of the above twoevents for an ARQ packet occurs during a predefined time interval. TheARQ transmitter 252 sends an ARQ PDU z to the H-ARQ transmitter 254(step 228). The H-ARQ transmitter 254 transmits the ARQ PDU z to theH-ARQ receiver 364 (step 230). The ARQ PDU z is successfully decoded andthe H-ARQ receiver 264 sends the ARQ PDU z to the ARQ receiver 262 (step232), and sends an ACK to the H-ARQ transmitter 254 (step 234). When itis determined that a NACK-to-ACK error is not reported during apredetermined time interval (step 236), the H-ARQ transmitter 254 sendsa local ACK to the ARQ transmitter 252 (step 238). The ARQ transmitter252 will discard the packet from a transmit buffer after receiving thelocal ACK from the H-ARQ transmitter 254.

In the above example of an H-ARQ assisted ARQ system, a complex layer 2(L2) status reporting mechanism is removed under the assumption that theNACK-to-ACK error is the only significant source of undetected packetloss. The ARQ transmitter will not be able to recover the packet forcases where the NACK-to-ACK error indicator is lost or a shared channelis lost due to a discontinuous transmission (DTX)/ACK error. Thuslossless transmission cannot be guaranteed.

Current downlink H-ARQ, (Release 5), does not specify the maximum numberof retransmissions for a packet. Thus, the H-ARQ transmitter or receiverdoes not know the maximum number of transmissions for each packet. Thereis an assumption that the ARQ transmitter and the H-ARQ transmitter havethe same PDU size. The H-ARQ transmitter informs the ARQ transmitter thesegment that is lost, (not the ARQ PDU). If the ARQ PDU isretransmitted, the H-ARQ transmitter will retransmit the completepacket, not only the missing segment. It is also unclear how to recoverthe last packet of the H-ARQ transmission.

SUMMARY

The present invention is related to a method and system for implementingH-ARQ-assisted ARQ in a wireless communication system. An H-ARQ receiverdetermines whether an H-ARQ NACK-to-ACK error occurs. When an H-ARQNACK-to-ACK error occurs, the H-ARQ receiver sends an H-ARQ errorindicator to the H-ARQ transmitter unless the number of retransmissionsof the failed packet has reached a maximum retransmission limit, amaximum time for delivery of the failed packet has expired and/or alifespan of the failed packet has expired. The H-ARQ transmitter triesto recover the failed packet. The H-ARQ transmitter sends a local NACKto the ARQ transmitter if the maximum retransmission limit has beenreached, the maximum delivery time has expired or the lifespan of thefailed packet has expired, so that the failed packet can be recovered atan ARQ level. The H-ARQ receiver sends a local NACK to the ARQ receiverif the H-ARQ receiver does not receive the failed packet before certainconditions occur. Based on reception of the local NAK, the ARQ receivermay send a status report to the ARQ transmitter for recovery of thefailed packet.

BRIEF DESCRIPTION OF THE DRAWINGS

A more detailed understanding of the invention may be had from thefollowing description of a preferred embodiment, given by way of exampleand to be understood in conjunction with the accompanying drawing(s)wherein:

FIG. 1 shows a conventional wireless communication system;

FIG. 2 shows an example of an H-ARQ-assisted ARQ operation proposed forthird generation partnership project (3GPP) standards; and

FIG. 3 is a signaling diagram of a process for implementing anH-ARQ-assisted ARQ operation in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The features of the present invention may be incorporated into anintegrated circuit (IC) or be configured in a circuit comprising amultitude of interconnecting components.

FIG. 3 is a signaling diagram of a process 400 for implementing anH-ARQ-assisted ARQ operation in a wireless communication system 300 inaccordance with the present invention. The system 300 includes atransmitter 310 and a receiver 320. The transmitter 310 includes an ARQtransmitter 312 and an H-ARQ transmitter 314. The receiver 320 includesan ARQ receiver 322 and an H-ARQ receiver 324.

In order to support the H-ARQ-assisted ARQ in accordance with thepresent invention, the following parameters are defined:

T_(ErrorIndicator): H-ARQ error indication timer is defined as theamount of time that an H-ARQ receiver should wait for a retransmissionof the failed packet before sending an HARQ error indicator. It ispreferable to keep the H-ARQ error indication timer constant for thewhole system for simple implementation. However, the H-ARQ errorindication timer may be adjusted based on the quality of service (QoS)requirements. For example, the length of the H-ARQ error indicationtimer may be linked to the scheduling priority.

N_(Retransmission): Maximum number of retransmissions allowed for apacket. The maximum number of retransmissions may be based on the QoSrequirements, and be configured per service type.

T_(Delivery): Maximum delivery time allowed for successful delivery ofthe packet after the first transmission. The maximum delivery time maybe based on the QoS requirements, (e.g., a block error rate, latency, orthe like), and be configured per service type.

T_(RecoverySync): For synchronous H-ARQ, a time within which the H-ARQreceiver expects to receive a failed packet after transmitting an H-ARQerror indicator.

T_(RecoveryAsync): For asynchronous H-ARQ, a time within which the H-ARQreceiver expects to receive a failed packet after transmitting an H-ARQerror indicator. The timer may be associated with the QoS requirements,and be configured per service type. For example, the length of the timermay be linked to the scheduling priority.

W_(HARQ): A window, (i.e., the number of packets), within which a failedpacket should be received. If the failed packet is not received withinW_(HARQ), it is assumed lost.

The transmitter 310 and the receiver 320 may also be given with aparameter for a lifespan of a packet, (i.e., the maximum time totransmit the packet). The parameters may be provided by a central nodeto the H-ARQ receiver 324 and the H-ARQ transmitter 314. If theparameters are defined per service type, the parameters may be given tothe H-ARQ receiver 324 and the H-ARQ transmitter 314 at the start ofthat service.

The maximum number of retransmissions and/or the lifespan of a packetmay be dynamically changed depending on the QoS requirements. Themaximum number of transmissions may be indicated by either explicitlyidentifying the number of transmissions in the associated signaling oridentifying a MAC flow that is associated with a configured maximumnumber of transmissions. In accordance with the first option, the numberof retransmissions per packet is indicated in the associated controlsignaling for the first transmission. In accordance with the secondoption, each MAC flow may be associated with a certain number ofretransmissions and by identifying the MAC flow in the associatedcontrol signaling for the first transmission, the maximum number oftransmissions may be indicated. If the second option is used, theidentified MAC flow is translated to the maximum number of transmissionsconfigured by the receiver. The maximum number of retransmissions mayalso be known by an H-ARQ process ID if specific H-ARQ processes arededicated to a MAC flow for a set of MAC flows. Alternatively, a flagmay be set in the associated signaling to indicate last transmission.

A process 400 for implementing an H-ARQ-assisted ARQ operation inaccordance with the present invention is explained hereafter withreference to FIG. 3. The H-ARQ transmitter 314 transmits a packet to theH-ARQ receiver 324 (step 402). If the packet is successfully received,the H-ARQ receiver 324 sends the packet to the ARQ receiver 322 (notshown in FIG. 3). If the packet is not successfully received, the H-ARQreceiver 324 sends a NACK to the H-ARQ transmitter 314 (step 404). Aftersending the NACK in step 404, the H-ARQ receiver 324 determines whetheran H-ARQ NACK-to-ACK error occurs (step 406). Upon detection of theH-ARQ NACK-to-ACK error, the H-ARQ receiver 324 generates, and sends, anH-ARQ NACK-to-ACK error indicator to the H-ARQ transmitter 314 (step408).

For synchronous H-ARQ transmission, the time of a H-ARQ retransmissionis known to the receiver. If the H-ARQ receiver 324 receives a newpacket when expecting retransmission of the failed packet, the H-ARQreceiver 324 determines that an H-ARQ NACK-to-ACK error occurs and sendsan H-ARQ NACK-to-ACK error indicator unless the failed packet has beentransmitted for the maximum number of retransmissions.

For asynchronous H-ARQ transmission, a timer T_(ErrorIndicator) is setat the H-ARQ receiver 324 when the maximum number of retransmission hasnot been reached and the H-ARQ receiver 324 sends a NACK to the H-ARQtransmitter 314 at step 404. If the failed packet is successfullyreceived before the timer T_(ErrorIndicator) expires, the timerT_(ErrorIndicator) is reset to zero and the H-ARQ NACK-to-ACK errorindicator is not generated. If the H-ARQ receiver 324 does notsuccessfully receive the failed packet before the timerT_(ErrorIndicator) expires, the H-ARQ receiver 324 determines that anH-ARQ NACK-to-ACK error occurs and sends an H-ARQ NACK-to-ACK errorindicator to the H-ARQ transmitter 314 unless the number oftransmissions of the failed packet has reached the maximumretransmission limit, the maximum delivery time for the packet,(T_(Delivery)), has expired, and/or the lifespan of the failed packethas expired.

The H-ARQ NACK-to-ACK error indicator is sent from the H-ARQ receiver324 to the H-ARQ transmitter 314 to inform about a NACK-to-ACKmisinterpretation at the H-ARQ transmitter 314. The H-ARQ NACK-to-ACKerror indicator is associated with a particular H-ARQ process and aparticular packet in the H-ARQ process. The H-ARQ NACK-to-ACK errorindicator contains H-ARQ process identity (ID) and a TSN to identify thepacket ID in the H-ARQ process.

For synchronous H-ARQ, the H-ARQ process ID and the TSN may be removedsince a fixed timing relationship between the failed transmission andthe error report can be used to associate the H-ARQ NACK-to-ACK errorindicator with an H-ARQ process ID and a packet TSN. For example, ifthere are four (4) synchronous H-ARQ processes, the H-ARQ NACK-to-ACKerror indicator may be sent after time t of receiving the packet with aTSN n for which the NACK-to-ACK error happened.

An H-ARQ NACK-to-ACK error indicator packet may be independent of theH-ARQ operation. This is achieved by sending the process identity (ifneeded) and time offset to identify reception time of the receivederror. Alternatively, the H-ARQ NACK-to-ACK error indicator may be sentas a physical layer signal at a fixed time offset after the reception ofthe received error packet.

If more than one packet may be sent simultaneously from the transmitter310 to the receiver 320, the packets have their own cyclic redundancycheck (CRC) and one H-ARQ NACK-to-ACK error indicator may be used tosend NACK-to-ACK error indications for several packets. Hence, the H-ARQNACK-to-ACK error indicator may contain multiple H-ARQ process IDs,associated packet TSNs and/or timing offset.

The H-ARQ NACK-to-ACK error indicator may have its own CRC to ensurereliable transmission. This allows MAC or RLC layer signaling for H-ARQNACK-to-ACK error indication. The H-ARQ NACK-to-ACK error indicatorpacket may be created either at H-ARQ or ARQ level.

Still referring to FIG. 3, to ensure receipt of the H-ARQ NACK-to-ACKerror indicator, the H-ARQ transmitter 314 may send an ACK to the H-ARQreceiver 324 (step 410). The H-ARQ receiver 324 may repeatedly send theH-ARQ NACK-to-ACK error indicator until the H-ARQ receiver 324 receivesan ACK from the H-ARQ transmitter 314 or radio link fails.

After receiving the H-ARQ NACK-to-ACK error indicator at step 408, theH-ARQ transmitter 314 tries to recover the error at an H-ARQ level byretransmitting the failed packet unless the maximum retransmission limithas reached, the maximum delivery time has expired, and/or the lifespanof the failed packet has expired (step 412). The H-ARQ transmitter 314may send a local NACK to the ARQ transmitter 312 so that the failedpacket can be recovered at an ARQ level (step 414). Preferably, theH-ARQ transmitter 314 sends the local NACK to the ARQ transmitter 312only if the maximum number of retransmissions has been reached, themaximum delivery time for transmission of the failed packet has expired,or the lifespan of the failed packet has expired.

In the prior art, upon successful delivery of a packet, the H-ARQreceiver 324 sends an ACK to the H-ARQ transmitter 314 and the H-ARQtransmitter 314 sends a local ACK to the ARQ transmitter 312. Inaccordance with the present invention, the H-ARQ transmitter 314 may ormay not send a local ACK to the ARQ transmitter 312 in such situation.

After sending the H-ARQ NACK-to-ACK error indicator at step 408, theH-ARQ receiver 324 determines at step 416 whether the H-ARQ receiver 324does not receive the failed packet successfully before at least one ofthe following conditions:

1) expiration of T_(RecoverySync) (for synchronous H-ARQ transmission)or T_(RecoveryAsync) (for asynchronous H-ARQ transmission);

2) receipt of a new H-ARQ packet with a sequence number which is higherthan the sequence number of the failed packet by W_(HARQ);

3) reaching the maximum number of retransmissions of the failed packet;

4) expiration of the timer T_(Delivery); and

5) expiration of the lifespan of the failed packet.

If at least one of the foregoing conditions occurs, the H-ARQ receiver324 sends a local NACK to the ARQ receiver 322 (step 418). Uponreception of the local NACK, the ARQ receiver 322 may send a statusreport to the ARQ transmitter 312 to recover the failed packet (step420). The mapping between an ARQ PDU and an H-ARQ PDU is not relevant aslong as the H-ARQ receiver 324 is able to identify the ARQ PDU thatneeds to be recovered.

The ARQ buffer at the ARQ transmitter 312 may be emptied after receivingthe status report from the ARQ receiver 322. The status report for thefailed packet contains the information about successfully receivedpackets. Alternatively, the ARQ receiver 322 may send a status reportafter receiving N consecutive packets successfully or expiration of atimer. Alternatively, the ARQ transmitter 312 may poll the ARQ receiver322 after transmitting the last packet in the buffer. The reason forpolling is to recover early from the NACK-to-ACK error at an H-ARQ levelfor the last packet. Setting the “Poll bit for the last packet” is aconfigurable parameter for a data flow.

In order to improve the recovery of the last packet in H-ARQtransmissions, a special small packet with a last packet indication maybe sent from the H-ARQ transmitter 314 after the H-ARQ buffer is empty.The transmission of the special packet with a last packet indicationensures early recovery of the loss of the last packet at the H-ARQlevel. The H-ARQ receiver 324 sends a response back to the H-ARQtransmitter 314 upon receiving the special packet. The response packetmay be a new packet generated at an H-ARQ level indicating the last TSNreceived. Alternatively, the response packet may be sent by using anH-ARQ error indication packet indicating that it is a response to thesmall packet.

Alternatively, in order to reduce the signaling overhead, a nulltransmission may be sent after the last data packet in an H-ARQtransmission queue to invoke the ACK check on the previous transmission.A null packet only includes control information (i.e., no payload). TheH-ARQ transmitter 314 transmits the null packet after reception of anH-ARQ ACK for the last data packet in the H-ARQ transmission queue. Oncethe H-ARQ receiver 324 receives a null packet, the H-ARQ receiver 324confirms reception of the last data packet as well as the null packet.If, at the H-ARQ receiver, the last packet was not successfully receivedand therefore a NACK was sent in response to the last packet and themaximum number of transmissions was not reached, the reception of thenull packet will allow the H-ARQ receiver 324 to detect the NACK-to-ACKerror.

The transmitter 310 and the receiver 320 may be a WTRU, a base stationor any other network entity in a WCDMA, CDMA2000 or long term evolution(LTE) of a third generation (3G) system. “WTRU” includes but is notlimited to a user equipment (UE), a mobile station, a fixed or mobilesubscriber unit, a pager, a cellular telephone, a personal dataassistant (PDA), a computer, or any other type of user device capable ofoperating in a wireless environment. “Base station” includes but is notlimited to a Node-B, a site controller, an access point or any othertype of interfacing device in a wireless environment.

Although the features and elements of the present invention aredescribed in the preferred embodiments in particular combinations, eachfeature or element can be used alone without the other features andelements of the preferred embodiments or in various combinations with orwithout other features and elements of the present invention. Themethods or flow charts provided in the present invention may beimplemented in a computer program, software, or firmware tangiblyembodied in a computer-readable storage medium for execution by ageneral purpose computer or a processor. Examples of computer-readablestorage mediums include a read only memory (ROM), a random access memory(RAM), a register, cache memory, semiconductor memory devices, magneticmedia such as internal hard disks and removable disks, magneto-opticalmedia, and optical media such as CD-ROM disks, and digital versatiledisks (DVDs).

Suitable processors include, by way of example, a general purposeprocessor, a special purpose processor, a conventional processor, adigital signal processor (DSP), a plurality of microprocessors, one ormore microprocessors in association with a DSP core, a controller, amicrocontroller, Application Specific Integrated Circuits (ASICs), FieldProgrammable Gate Arrays (FPGAs) circuits, any other type of integratedcircuit (IC), and/or a state machine.

A processor in association with software may be used to implement aradio frequency transceiver for use in a wireless transmit receive unit(WTRU), user equipment (UE), terminal, base station, radio networkcontroller (RNC), or any host computer. The WTRU may be used inconjunction with modules, implemented in hardware and/or software, suchas a camera, a video camera module, a videophone, a speakerphone, avibration device, a speaker, a microphone, a television transceiver, ahands free headset, a keyboard, a Bluetooth® module, a frequencymodulated (FM) radio unit, a liquid crystal display (LCD) display unit,an organic light-emitting diode (OLED) display unit, a digital musicplayer, a media player, a video game player module, an Internet browser,and/or any wireless local area network (WLAN) module.

1. In a wireless communication system including a transmitter and areceiver, the transmitter including a hybrid automatic repeat request(H-ARQ) transmitter and an automatic repeat request (ARQ) transmitter,the receiver including an H-ARQ receiver and an ARQ receiver, a methodfor implementing H-ARQ-assisted ARQ, the method comprising: an H-ARQreceiver determining whether an H-ARQ negative acknowledgement(NACK)-to-positive acknowledgement (ACK) error occurs; and the H-ARQreceiver sending an H-ARQ NACK-to-ACK error indicator to the H-ARQtransmitter when an H-ARQ NACK-to-ACK error occurs unless at least oneof the following has occurred: the number of retransmissions of a failedpacket has reached a maximum retransmission limit, a maximum time fordelivery of the failed packet has expired and a lifespan of the failedpacket has expired.
 2. The method of claim 1 wherein the H-ARQNACK-to-ACK error indicator is associated with an H-ARQ process identity(ID) and the failed packet at the H-ARQ transmitter.
 3. The method ofclaim 2 wherein the H-ARQ NACK-to-ACK error indicator includes the H-ARQprocess ID and a transmission sequence number of the failed packet. 4.The method of claim 2 wherein the H-ARQ NACK-to-ACK error indicator issent with a fixed timing offset with respect to transmission of thefailed packet.
 5. The method of claim 1 wherein transmission of theH-ARQ NACK-to-ACK error indicator and transmission of the failed packetare independent.
 6. The method of claim 1 wherein the H-ARQ NACK-to-ACKerror indicator is sent via at least one of physical layer signaling, amedium access control (MAC) layer signaling and a radio link control(RLC) layer signaling.
 7. The method of claim 1 wherein more than onepacket is transmitted from the H-ARQ transmitter to the H-ARQ receiversimultaneously and the H-ARQ NACK-to-ACK error indicator indicates H-ARQNACK-to-ACK errors of more than one packet.
 8. The method of claim 1wherein the H-ARQ NACK-to-ACK error indicator is sent along with acyclic redundancy check (CRC).
 9. The method of claim 1 wherein theH-ARQ NACK-to-ACK error indicator is generated by one of the H-ARQreceiver and an ARQ receiver.
 10. The method of claim 1 furthercomprising: the H-ARQ transmitter sending an ACK to the H-ARQ receiverupon receipt of the H-ARQ NACK-to-ACK error indicator.
 11. The method ofclaim 10 wherein the H-ARQ receiver sends the H-ARQ NACK-to-ACK errorindicator repeatedly if the H-ARQ receiver does not successfully receivethe ACK for the H-ARQ NACK-to-ACK error indicator and a radio linkbetween the H-ARQ transmitter and the H-ARQ receiver does not fail. 12.The method of claim 1 wherein the H-ARQ receiver sends the H-ARQNACK-to-ACK error indicator if the H-ARQ receiver receives a new packetvia the same H-ARQ process assigned for the failed packet instead ofretransmission of the failed packet.
 13. The method of claim 1 whereinthe H-ARQ receiver sends the H-ARQ NACK-to-ACK error indicator if theH-ARQ receiver does not receive the failed packet until an errorindication timer expires, the error indication timer being set when aNACK is sent to the H-ARQ transmitter.
 14. The method of claim 1 furthercomprising: the H-ARQ transmitter retransmitting the failed packet untilthe failed packet is successfully delivered unless at least one of thefollowing has occurred: the maximum retransmission limit has reached,the maximum delivery time has expired and the lifespan of the failedpacket has expired.
 15. The method of claim 14 further comprising: theH-ARQ transmitter sending a local NACK to the ARQ transmitter if themaximum retransmission limit has reached, the maximum delivery time hasexpired or the lifespan of the failed packet has expired, so that thefailed packet is recovered at an ARQ level.
 16. The method of claim 1further comprising: the H-ARQ receiver setting a recovery timer when theH-ARQ receiver sends the H-ARQ NACK-to-ACK error indicator; and theH-ARQ receiver sending a local NACK to the ARQ receiver if the H-ARQreceiver does not receive the failed packet before the recovery timerexpires.
 17. The method of claim 16 further comprising: the ARQ receiversending a status report to the ARQ transmitter for recovery of thefailed packet.
 18. The method of claim 1 further comprising: the H-ARQreceiver sending a local NACK to the ARQ receiver if the H-ARQ receiverdoes not receive the failed packet until the H-ARQ receiver receives apacket with a sequence number higher than a sequence number of thefailed packet by a predetermined number.
 19. The method of claim 18further comprising: the ARQ receiver sending a status report to the ARQtransmitter for recovery of the failed packet.
 20. The method of claim 1further comprising: the H-ARQ receiver sending a local NACK to the ARQreceiver if the H-ARQ receiver does not receive the failed packet untilthe number of retransmissions of the failed packet reaches a maximumretransmission limit for the failed packet.
 21. The method of claim 20further comprising: the ARQ receiver sending a status report to the ARQtransmitter for recovery of the failed packet.
 22. The method of claim 1further comprising: the H-ARQ receiver sending a local NACK to the ARQreceiver if the H-ARQ receiver does not receive the failed packet untila maximum time for delivery of the failed packet expires.
 23. The methodof claim 20 further comprising: the ARQ receiver sending a status reportto the ARQ transmitter for recovery of the failed packet.
 24. The methodof claim 1 further comprising: the ARQ receiver sending a status reportwhen the ARQ receiver receives a predetermined number of packetssuccessfully.
 25. The method of claim 1 further comprising: the ARQreceiver sending a status report when a status reporting timer expires.26. The method of claim 1 further comprising: the ARQ transmitterrequesting a status report from the ARQ receiver; and the ARQ receiversending a status report to the ARQ transmitter.
 27. The method of claim26 wherein the ARQ transmitter requests the status report aftertransmitting a last packet.
 28. The method of claim 1 furthercomprising: the H-ARQ transmitter sending a small packet with a lastpacket indication after sending a last packet in a buffer; and the H-ARQreceiver sending a response to the small packet, whereby a recovery ofthe last packet is ensured by the small packet.
 29. The method of claim28 wherein the small packet is a null transmission.
 30. The method ofclaim 28 wherein the response to the small packet is transmitted byusing the H-ARQ NACK-to-ACK error indicator.
 31. The method of claim 1wherein parameters for the maximum retransmission limit, the maximumtime for delivery of a packet and a lifespan of a packet are configuredby a central controlling entity.
 32. The method of claim 31 wherein theparameters are configured when the transmitter is active.
 33. The methodof claim 31 wherein the parameters are configured at the start of aservice.
 34. The method of claim 31 wherein the parameters areconfigured dynamically depending on quality of service (QoS) requirementof a packet.
 35. The method of claim 31 wherein the maximumretransmission limit of a packet is indicated by identifying aparticular medium access control (MAC) flow associated with a specificmaximum retransmission limit in an associated control signaling for thefirst transmission.
 36. The method of claim 31 wherein the maximumretransmission limit of a packet is explicitly indicated in anassociated control signaling for the first transmission.
 37. A wirelesscommunication system for implementing hybrid automatic repeat request(H-ARQ)-assisted automatic repeat request (ARQ), the system comprising:a receiver including an H-ARQ receiver and an ARQ receiver, the H-ARQreceiver being configured to determine whether an H-ARQ negativeacknowledgement (NACK)-to-positive acknowledgement (ACK) error occursand send an H-ARQ NACK-to-ACK error indicator to an H-ARQ transmitterunless at least one of the following has occurred: the number ofretransmissions of a failed packet has reached a maximum retransmissionlimit, a maximum time for delivery of the failed packet has expired anda lifespan of the failed packet has expired; and a transmitter includingthe H-ARQ transmitter and an ARQ transmitter.
 38. The system of claim 37wherein the H-ARQ NACK-to-ACK error indicator is associated with anH-ARQ process identity (ID) and the failed packet at the H-ARQtransmitter.
 39. The system of claim 38 wherein the H-ARQ NACK-to-ACKerror indicator includes the H-ARQ process ID and a transmissionsequence number of the failed packet.
 40. The system of claim 38 whereinthe H-ARQ NACK-to-ACK error indicator is sent with a fixed timing offsetwith respect to transmission of the failed packet.
 41. The system ofclaim 37 wherein transmission of the H-ARQ NACK-to-ACK error indicatorand transmission of the failed packet are independent.
 42. The system ofclaim 37 wherein the H-ARQ NACK-to-ACK error indicator is sent via atleast one of physical layer signaling, a medium access control (MAC)layer signaling and a radio link control (RLC) layer signaling.
 43. Thesystem of claim 37 wherein the H-ARQ transmitter and the H-ARQ receiverare configured to transmit and receive more than one packetsimultaneously and the H-ARQ receiver is configured to send the H-ARQNACK-to-ACK error indicator indicating H-ARQ NACK-to-ACK errors of morethan one packet.
 44. The system of claim 37 wherein the H-ARQNACK-to-ACK error indicator is sent along with a cyclic redundancy check(CRC).
 45. The system of claim 37 wherein the H-ARQ NACK-to-ACK errorindicator is generated by one of the H-ARQ receiver and an ARQ receiver.46. The system of claim 37 wherein the H-ARQ transmitter is configuredto send an ACK to the H-ARQ receiver upon receipt of the H-ARQNACK-to-ACK error indicator.
 47. The system of claim 46 wherein theH-ARQ receiver sends the H-ARQ NACK-to-ACK error indicator repeatedlyuntil the H-ARQ receiver successfully receives the ACK for the H-ARQNACK-to-ACK error indicator.
 48. The system of claim 47 wherein theH-ARQ receiver sends the H-ARQ NACK-to-ACK error indicator if the H-ARQreceiver receives a new packet via the same H-ARQ process assigned forthe failed packet instead of retransmission of the failed packet. 49.The system of claim 47 wherein the H-ARQ receiver sends the H-ARQNACK-to-ACK error indicator if the H-ARQ receiver does not receive thefailed packet until an error indication timer expires, the errorindication timer being set when a NACK is sent to the H-ARQ transmitter.50. The system of claim 47 wherein the H-ARQ transmitter retransmits thefailed packet until the failed packet is successfully delivered unlessat least one of the following has occurred: the maximum retransmissionlimit has reached, the maximum delivery time has expired and thelifespan of the failed packet has expired.
 51. The system of claim 50wherein the H-ARQ transmitter sends a local NACK to the ARQ transmitterif the maximum retransmission limit has reached, the maximum deliverytime has expired or the lifespan of the failed packet has expired, sothat the failed packet is recovered at an ARQ level.
 52. The system ofclaim 47 wherein the H-ARQ receiver sets a recovery timer when the H-ARQreceiver sends the H-ARQ NACK-to-ACK error indicator and sends a localNACK to the ARQ receiver if the H-ARQ receiver does not receive thefailed packet before the recovery timer expires.
 53. The system of claim52 wherein the ARQ receiver sends a status report to the ARQ transmitterfor recovery of the failed packet.
 54. The system of claim 47 whereinthe H-ARQ receiver sends a local NACK to the ARQ receiver if the H-ARQreceiver does not receive the failed packet until the H-ARQ receiverreceives a packet with a sequence number higher than a sequence numberof the failed packet by a predetermined number.
 55. The system of claim54 wherein the ARQ receiver sends a status report to the ARQ transmitterfor recovery of the failed packet.
 56. The system of claim 37 whereinthe H-ARQ receiver sends a local NACK to the ARQ receiver if the H-ARQreceiver does not receive the failed packet until the number ofretransmissions of the failed packet reaches a maximum retransmissionlimit for the failed packet.
 57. The system of claim 56 wherein the ARQreceiver sends a status report to the ARQ transmitter for recovery ofthe failed packet.
 58. The system of claim 57 wherein the H-ARQ receiversends a local NACK to the ARQ receiver if the H-ARQ receiver does notreceive the failed packet until a maximum time for delivery of thefailed packet expires.
 59. The system of claim 56 wherein the ARQreceiver sends a status report to the ARQ transmitter for recovery ofthe failed packet.
 60. The system of claim 56 wherein the ARQ receiversends a status report when the ARQ receiver receives a predeterminednumber of packets successfully.
 61. The system of claim 37 wherein theARQ receiver sends a status report when a status reporting timerexpires.
 62. The system of claim 37 wherein the ARQ transmitter requestsa status report from the ARQ receiver and the ARQ receiver sends astatus report to the ARQ transmitter.
 63. The system of claim 62 whereinthe ARQ transmitter requests the status report after transmitting a lastpacket.
 64. The system of claim 37 wherein the H-ARQ transmitter sends asmall packet with a last packet indication after sending a last packetin a buffer and the H-ARQ receiver sends a response to the small packet,whereby a recovery of the last packet is ensured by the small packet.65. The system of claim 64 wherein the small packet is a nulltransmission.
 66. The system of claim 64 wherein a response to the smallpacket is transmitted by using the H-ARQ NACK-to-ACK error indicator.67. The system of claim 37 wherein parameters for at least one of themaximum retransmission limit, the maximum time for delivery of a packetand a lifespan of a packet are configured by a central controllingentity.
 68. The system of claim 67 wherein the parameters are configuredwhen the receiver is active.
 69. The system of claim 67 wherein theparameters are configured at the start of a service.
 70. The system ofclaim 67 wherein the parameters are configured dynamically depending onquality of service (QoS) requirement of a packet.
 71. The system ofclaim 67 wherein the maximum retransmission limit of a packet isindicated by identifying a particular medium access control (MAC) flowassociated with a specific maximum retransmission limit in an associatedcontrol signaling for the first transmission.
 72. The system of claim 67wherein the maximum retransmission limit of a packet is explicitlyindicated in an associated control signaling for the first transmission.73. A receiver for implementing hybrid automatic repeat request(H-ARQ)-assisted automatic repeat request (ARQ), the receivercomprising: an ARQ receiver; and an H-ARQ receiver configured todetermine whether an H-ARQ negative acknowledgement (NACK)-to-positiveacknowledgement (ACK) error occurs and send an H-ARQ NACK-to-ACK errorindicator to an H-ARQ transmitter unless at least one of the followinghas occurred: the number of retransmissions of a failed packet hasreached a maximum retransmission limit, a maximum time for delivery ofthe failed packet has expired and a lifespan of the failed packet hasexpired.
 74. The receiver of claim 73 wherein the H-ARQ NACK-to-ACKerror indicator is associated with an H-ARQ process identity (ID) andthe failed packet at the H-ARQ transmitter.
 75. The receiver of claim 74wherein the H-ARQ NACK-to-ACK error indicator includes the H-ARQ processID and a transmission sequence number of the failed packet.
 76. Thereceiver of claim 74 wherein the H-ARQ NACK-to-ACK error indicator issent with a fixed timing offset with respect to transmission of thefailed packet.
 77. The receiver of claim 73 wherein transmission of theH-ARQ NACK-to-ACK error indicator and transmission of the failed packetare independent.
 78. The receiver of claim 73 wherein the H-ARQNACK-to-ACK error indicator is sent via at least one of physical layersignaling, a medium access control (MAC) layer signaling and a radiolink control (RLC) layer signaling.
 79. The receiver of claim 73 whereinthe H-ARQ receiver is configured to receive more than one packetsimultaneously and send the H-ARQ NACK-to-ACK error indicator indicatingH-ARQ NACK-to-ACK errors of more than one packet.
 80. The receiver ofclaim 73 wherein the H-ARQ NACK-to-ACK error indicator is sent alongwith a cyclic redundancy check (CRC).
 81. The receiver of claim 73wherein the H-ARQ NACK-to-ACK error indicator is generated by one of theH-ARQ receiver and the ARQ receiver.
 82. The receiver of claim 73wherein the H-ARQ receiver sends the H-ARQ NACK-to-ACK error indicatorrepeatedly until the H-ARQ receiver successfully receives anacknowledgement (ACK) for the H-ARQ NACK-to-ACK error indicator.
 83. Thereceiver of claim 73 wherein the H-ARQ receiver sends the H-ARQNACK-to-ACK error indicator if the H-ARQ receiver receives a new packetvia the same H-ARQ process assigned for the failed packet instead ofretransmission of the failed packet.
 84. The receiver of claim 73wherein the H-ARQ receiver sends the H-ARQ NACK-to-ACK error indicatorif the H-ARQ receiver does not receive the failed packet until an errorindication timer expires, the error indication timer being set when aNACK is sent to the H-ARQ transmitter.
 85. The receiver of claim 73wherein the H-ARQ receiver sets a recovery timer when the H-ARQ receiversends the H-ARQ NACK-to-ACK error indicator and sends a local NACK tothe ARQ receiver if the H-ARQ receiver does not receive the failedpacket before the recovery timer expires.
 86. The receiver of claim 85wherein the ARQ receiver sends a status report to the ARQ transmitterfor recovery of the failed packet.
 87. The receiver of claim 73 whereinthe H-ARQ receiver sends a local NACK to the ARQ receiver if the H-ARQreceiver does not receive the failed packet until the H-ARQ receiverreceives a packet with a sequence number higher than a sequence numberof the failed packet by a predetermined number.
 88. The receiver ofclaim 87 wherein the ARQ receiver sends a status report to the ARQtransmitter for recovery of the failed packet.
 89. The receiver of claim73 wherein the H-ARQ receiver sends a local NACK to the ARQ receiver ifthe H-ARQ receiver does not receive the failed packet until the numberof retransmissions of the failed packet reaches a maximum retransmissionlimit for the failed packet.
 90. The receiver of claim 89 wherein theARQ receiver sends a status report to the ARQ transmitter for recoveryof the failed packet.
 91. The receiver of claim 73 wherein the H-ARQreceiver sends a local NACK to the ARQ receiver if the H-ARQ receiverdoes not receive the failed packet until a maximum time for delivery ofthe failed packet expires.
 92. The receiver of claim 91 wherein the ARQreceiver sends a status report to the ARQ transmitter for recovery ofthe failed packet.
 93. The receiver of claim 73 wherein the ARQ receiversends a status report when the ARQ receiver receives a predeterminednumber of packets successfully.
 94. The receiver of claim 73 wherein theARQ receiver sends a status report when a status reporting timerexpires.
 95. A transmitter for implementing hybrid automatic repeatrequest (H-ARQ)-assisted automatic repeat request (ARQ), the transmittercomprising: an ARQ transmitter; and an H-ARQ transmitter configured toreceive an H-ARQ negative acknowledgement (NACK)-to-positiveacknowledgement (ACK) error indicator, wherein at least one of the ARQtransmitter and the H-ARQ transmitter is configured to recover a failedpacket corresponding to the H-ARQ NACK-to-ACK error.
 96. The transmitterof claim 95 wherein the H-ARQ transmitter is configured to send an ACKto the H-ARQ receiver upon receipt of the H-ARQ NACK-to-ACK errorindicator.
 97. The transmitter of claim 95 wherein the H-ARQ transmitterretransmits the failed packet until the failed packet is successfullydelivered unless at least one of the following has occurred: the maximumretransmission limit has reached, the maximum delivery time has expiredand the lifespan of the failed packet has expired.
 98. The transmitterof claim 95 wherein the H-ARQ transmitter sends a local NACK to the ARQtransmitter if the maximum retransmission limit has reached, the maximumdelivery time has expired or the lifespan of the failed packet hasexpired, so that the failed packet is recovered at an ARQ level.
 99. Thetransmitter of claim 95 wherein the ARQ transmitter requests a statusreport from the ARQ receiver.
 100. The transmitter of claim 95 whereinthe ARQ transmitter requests the status report after transmitting a lastpacket.
 101. The transmitter of claim 95 wherein the H-ARQ transmittersends a small packet with a last packet indication after sending a lastpacket in a buffer, whereby a recovery of the last packet is ensured bythe small packet.
 102. The transmitter of claim 101 wherein the smallpacket is a null transmission.
 103. The transmitter of claim 101 whereina response to the small packet is transmitted by using the H-ARQNACK-to-ACK error indicator.